Method and apparatus for using rotational movement amount of mobile device and computer-readable recording medium for storing computer program

• US 7,747,348 B2
• Filed: 09/08/2004
• Issued: 06/29/2010
• Est. Priority Date: 12/23/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kwon, Woong, Roh, Kyung-shik, Han, Woo-sup, Shim, Young-bo
• Primary Examiner(s): Tran; Khoi
• Assistant Examiner(s): Peche; Jorge O
• Application Number:
  US10/935,592
• Publication Number:
  US 20050137750A1
• Time in Patent Office: 2,120 Days
• Field of Search: 700/245, 700/253, 700/254, 700/259, 700/900, 701/25, 701/28, 701/207, 701/23, 701/200, 701/208, 701/209, 340/995.24, 340/995.22, 324/200, 324/202, 318/568.12, 318/568.1, 318/568.15, 318/568.16, 382/104, 382/106, 382/209
• US Class Current: 700/245
• CPC Class Codes: G05D 1/0253 extracting relative motion information from a plurality of images taken successively, e.g. visual odometry, optical flow determining position or orientation from images G06T7/70
• CPC Class Codes: G05D 1/027 comprising intertial navigation means, e.g. azimuth detector inertial navigation G01C21/16; inertial navigation combined with non-inertial navigation instruments G01C21/165
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00
• CPC Class Codes: Y10S 700/90 Special robot structural element

Abstract

Provided is a method of using a rotational movement amount of a mobile device including obtaining images at two different points on a path along which the mobile device moves, searching for matching points with respect to the obtained images and obtaining an image coordinate value of each of the matching points, sensing linear movement of the mobile device and obtaining a linear movement amount using a result of sensing, and obtaining the rotational movement amount using the image coordinate values and the linear movement amount.

Claims

1. A method of determining a rotational movement amount of a mobile device comprising:

generating a posture initialization signal of the mobile device;

determining whether a posture of the mobile device is required by using a correction checking device;

obtaining images at two different points on a path along which the mobile device moves by using an image obtaining device in response to the correction checking unit when a correction of the posture of the mobile device is required;

searching for matching points with respect to the obtained images and obtaining an image coordinate value of each of the matching points;

sensing linear movement of the mobile device and obtaining a linear movement amount from a sensing device; and

obtaining the rotational movement amount by calculating the image coordinate values together with the linear movement amount; and

updating posture of the mobile device using the linear movement amount and the rotational movement amount by using a posture updating device;

determining whether the mobile device arrived at a target position by using a position checking device and outputting a result to the correction checking device; and

generating a movement control signal by using a control unit upon determining the correction of the posture of the mobile device is not required,

wherein the calculating of the image coordinate values together with the linear movement amount includes multiplying the image coordinate values with a cross product calculation of the linear movement amount.

2. The method of claim 1, wherein the mobile device moves from a time at which the image coordinate value is obtained until the posture is updated.

3. The method of claim 1, wherein the mobile device stops from a time at which the image coordinate value is obtained until the posture is updated.

4. The method of claim 1, further comprising:

starting movement of the mobile device.

5. The method of claim 1, further comprising moving the mobile device and proceeding to determining whether the mobile device arrives at the target position if it is determined that the posture of the mobile device does not need to be corrected.

6. The method of claim 1, wherein the number of matching points is eight and the number of minimum required matching points is eight.

7. The method of claim 6, wherein the number of matching points is set to be an integral multiple of the number of minimum required matching points.

8. The method of claim 1, wherein the number of matching points is two and the number of a minimum required matching points is two.

9. The method of claim 1, wherein path formed by the two points is a straight line.

10. The method of claim 1, wherein the rotational movement amount of the mobile device is obtained using a conversion matrix (R_1,2) that is obtained as follows,

$\begin{array}{c}[\frac{\stackrel{\_}{u_{i,1}}}{f_{\mathrm{sx}}}\end{array}$

a i ⁢

v i , 1 _ f sy ] ·

R 2 , 1 ·

[ u i , 2 f sx ⁢

1 ⁢

v i , 2 f sy ] T = 0 , wherein ⁢

[ u i , 1 _ f sx ⁢

a i ⁢

v i , 1 _ f sy ] = [ u i , 1 f sx ⁢

1 ⁢

v i , 1 f sy ] ⁢

s ⁡

( t 1 , 2 1 )

and i=1, . . . , l,l denotes the number of the minimum required matching points, and ¹t_1,2 denotes a linear movement amount expressed as Coord. 1, u_i,2, u_i,1, v_i,1, and v_i,2 denote the image coordinate values, s( ) denotes a skew-symmetric matrix defined to express the cross product calculation of a vector, R_2,1 is an inverse matrix of R_1,2,

$f_{\mathrm{sx}}=\frac{f_1}{s_x},f_{\mathrm{sy}}=\frac{f_2}{s_y},$

f₁ and f₂ denote focal distances from the two points, s_x and s_y denote scale factors, T denotes a transposed matrix, and a₁ denotes a constant.

11. An apparatus for determining a rotational movement amount of a mobile device comprising:

a correction checking portion which determines whether a correction of a posture of the mobile device is required;

an image obtaining portion which obtains images from two different points on a path along which the mobile device moves, upon determining that the posture of the mobile device is required;

a coordinate value generating portion which searches for matching points with respect to the obtained images and generates an image coordinate value for each of the matching points;

a sensing portion which senses linear movement of the mobile device;

a movement amount generating portion which generates a linear movement amount from a result of sensing and generates the rotational movement amount by calculating the image coordinate values together with the linear movement amount;

a posture updating portion which updates posture of the mobile device from the linear movement amount and the rotational movement amount generated by the movement amount generating portion and outputs an updated result;

a position checking portion which determines whether the mobile device arrived at a target position and outputting a result to the correction checking portion; and

a control portion generating a movement control signal upon determining that the correction of the posture of the mobile device is not required, and generating a posture initialization signal,

wherein the calculating of the image coordinate values together with the linear movement amount includes multiplying the image coordinate values with a cross product calculation of the linear movement amount.

12. The apparatus of claim 11, wherein the image obtaining portion obtains the images in response to a result of determining of the correction checking portion.

13. The apparatus of claim 12, wherein the control portion generates a correction control signal;

and

the position checking portion checks whether the mobile device arrives at a target position in response to an update completion signal that indicates completion of update of the posture and is received from the posture updating portion,

wherein the mobile device moves in response to the movement control signal, the posture updating portion initializes the posture in response to the posture initialization signal, and the correction checking portion checks whether to correct the posture in response to the correction control signal or a result of checking checked by the position checking portion.

14. The apparatus of claim 13, wherein the control portion generates the movement control signal in response to a result of checking by the correction checking portion and controls a checking operation of the position checking portion.

15. The apparatus of claim 11, wherein

the control portion which generates an obtainment control signal;

and

the position checking portion which checks whether the mobile device arrives at a target position in response to an update completion signal that indicates completion of update and is received from the posture updating portion,

wherein the mobile device moves in response to the movement control signal, the posture updating portion initializes the posture in response to the posture initialization signal, and the image obtaining portion obtains the image in response to the obtainment control signal and a result of checking by the position checking portion.

16. A non-transitory computer-readable storage medium storing at least one computer program to control at least one processing device to implement a method of determining a rotational movement amount of a mobile device, the method comprising:

determining whether a posture of the mobile device is required;

obtaining images at two different points on a path along which the mobile device moves, upon determining that the posture of the mobile device is required;

searching for matching points with respect to the obtained images and generating an image coordinate value of each of the matching points;

sensing linear movement of the mobile device and generating a linear movement amount from the sensing;

generating the rotational movement amount by calculating the image coordinate values together with the linear movement amount;

updating posture of the mobile device using the linear movement amount and the rotational movement amount,

determining whether the mobile device arrived at a target position and outputting a result; and

generating a movement control signal upon determining that the correction of the posture of the mobile device is not required,

wherein the calculating of the image coordinate values together with the linear movement amount includes multiplying the image coordinate values with a cross product calculation of the linear movement amount.